1. Field
The present disclosure relates to a graphene-nanomaterial composite, an electrode and an electric device including the same, and/or a method of manufacturing the graphene-nanomaterial composite.
2. Description of the Related Art
Secondary batteries and electrochemical capacitors (ECs) among electric devices are representative of energy storage devices using an electrochemical principle. The ECs use a charge phenomenon resulting from simple migration of ions across an interface between an electrode and an electrolyte, or a surface chemical reaction. When an electrolyte solution exists between metallic electrodes, electrolyte ions are adsorbed on the surface of the electrode during the application of voltage to electrically charge the EC. Therefore, the EC is receiving attention as an advanced energy storage device that may be used as an auxiliary battery or a device for replacing a battery due to the possibility of rapid charging and discharging, and characteristics of high charge and discharge efficiency and semi-permanent cycle lifetime.
A supercapacitor is one type of electrochemical capacitor, and is classified as an electric double layer capacitor (EDLC), in which electric charging and discharging occur by physical adsorption and desorption occurring on the surface of an electrode, and as a pseudo capacitor using a rapid and reversible oxidation-reduction reaction of metal oxide.
A core material controlling the capacity performance of a device among electrode materials of the supercapacitor is an electrode active material. In general, a porous carbon-based material having a high specific surface area has been used as a typical electrode material, and activated carbon having a high specific surface area of about 1,500 m2/g to about 2,000 m2/g is now commercially used. However, with respect to the carbon-based materials, because the distribution of pores may be non-uniform, low electrode density may be observed due to the high specific surface area, and a binder material, such as a polymer, may be mixed for the formation of an electrode, and thus, conductivity may be reduced.
Therefore, there is a need to develop an electrode having improved density and having a distribution of pores and an electrode structure that facilitate the diffusion of electrolyte ions.